Справочник Пользователя для Apple MD094LL/A
iMac (27-inch, Mid 2010) Symptom Charts — Display
53
2010-09-09
Display
Backlight Issue/No Backlight
Unlikely cause: hard drive, optical drive, speakers, camera, microphone
Quick Check
Symptoms
Quick Check
Backlight Issue/No Backlight
• No image
• Partial backlight failure
• Backlight flickers
• Display dim
• No image
• Partial backlight failure
• Backlight flickers
• Display dim
1. Check for Software Update.
2. Verify that System Preferences > Displays >
2. Verify that System Preferences > Displays >
Brightness control setting is above minimum.
3. If no image on built-in display, connect external
display to verify if iMac video circuitry is
functioning. If no image visible on external
display, go to
symptom flow under
Startup and Power troubleshooting.
Deep Dive
Check
Result
Action
Code
1. Verify boot chime present and
fans running when computer
powered ON. (Reset SMC, clear
PRAM or reseat Backup Battery
if necessary for proper boot
up.)
Yes
Power on self test OK.
Go to step 2.
No
Go to
symptom flow.
2. Verify if image is visible on
built-in LCD panel, with
adjustable backlight level.
Yes
Video is present. Verify system
functionality and return to
user, or go to appropriate
troubleshooting flow.
No
Go to step 3.
3. Connect supported external
display to rear Mini DisplayPort
video port (Use known-good
MiniDisplay to VGA or DVI
adapters if needed) . Verify if
image appears on external
display when system is booted.
Yes
External display detected
by system. Video circuitry
on logic board appears
functional. Go to step 4.
No
Go to
symptom
flow.
4. Verify if LCD backlight is ON
by looking for faint glow
from display when viewed in
darkened room with brightness
set at maximum.
Yes
LED backlight is functioning.
Go to step 7.
No
Go to step 5.